The present disclosure relates to vacuum cleaners. More particularly, the present disclosure relates to dual stage cyclonic vacuum cleaners used for suctioning dirt and debris from carpets and floors. Such vacuum cleaners can be upright, canister, hand-held or stationary, built into a house. Moreover, cyclonic designs have also been used on carpet extractors and “shop” type vacuum cleaners.
Upright vacuum cleaners are well known in the art. The two major types of traditional vacuum cleaners are a soft bag vacuum cleaner and a hard shell vacuum cleaner. In the hard shell vacuum cleaner, a vacuum source generates the suction required to pull dirt from the carpet or floor being vacuumed through a suction opening and into a filter bag or a dust cup housed within the hard shell upper portion of the vacuum cleaner. After multiple uses of the vacuum cleaner, the filter bag must be replaced or the dust cup emptied.
To avoid the need for vacuum filter bags, and the associated expense and inconvenience of replacing the filter bag, another type of upright vacuum cleaner utilizes cyclonic air flow and perhaps one or more filters, rather than a replaceable filter bag, to separate the dirt and other particulates from the suction air stream. If filters are used, they would need infrequent replacement.
The cyclonic air flow can be generated from a single stage cyclonic separator or a multi-stage cyclonic separator. One of the most common challenges regarding the design of a multi-stage cyclonic separator unit is the dust collector, which needs to be compact and easily serviceable by the user. The dust collector generally includes a first cyclonic separator, a plurality of second cyclonic separators and at least one particle collector. The position of the second cyclonic separators poses additional design concerns. For example, the second cyclones can be positioned above the first cyclone. But, this can increase the overall height of the dust collector, which is especially disadvantageous for canister vacuum cleaners. Alternatively, the second cyclones can be positioned around the first cyclone to form a separate, second particle collector. However, this can increase the overall width of the particle collector, which is especially disadvantageous for upright vacuum cleaners. Also, with such a design, the diameter of the first particle collector remains relatively small, which is disadvantageous from the standpoint of separation efficiency. As another alternative, the second cyclones can be positioned inside and at least partially below a top wall of the first cyclone. However with such a design, the second cyclones are hidden and difficult to service due to lack of access.
Therefore, while some prior art cyclonic air flow vacuum cleaner designs and constructions are acceptable, the need exists for continued improvements and alternative designs for such vacuum cleaners. For example, it would be desirable to simplify assembly, improve filtering and dirt removal, and allow easier maintenance of such cleaners.
Accordingly, the present disclosure provides an improved dual stage cyclonic air flow design which overcomes certain difficulties with the prior art designs while providing better and more advantageous overall results.